A gas turbine engine comprises stator stages and rotor stages. The stator stages are located adjacent to the rotor stages. In order to provide a proper sealing of the stator stage between a high pressure side and a low pressure side which are divided by the stator stage, a central section, in particular the static diaphragm, of the stator stage should accurately be located relative to the rotating components, i.e. a turbine shaft and the adjacent rotor stages. Moreover, supporting elements of the central section should also allow a relative radial expansion while maintaining an accurate circumferential location. Furthermore, a proper balancing of the axial loads caused by the pressure differential across the stator stage should be achieved. It is currently known to use a pre-assembling arrangement where the central section of a stator stage is adjusted by key blocks and dowels that are drilled and fixed to the stator stage assembly. During the pre-assembling, an interim carrier ring substitutes a stator casing and vane sections with key block are positioned in the interim carrier ring. Subsequently, the vane segments are positioned by location pins in the casing and the central section is manually positioned to gain concentricity with regards to the casing. After aligning a through hole is drilled through the key blocks at the overlapping portions of the central section and the vane section. After the drilling the assembly is disassembled, cleaned and the vane segments are inserted in the central section. Next, a dowel is fixed into the through hole in order to fix the relative position between the central section and the vane section.
Such an assembling needed three days for the assembling. Moreover, the assembling, cleaning and re-assembling adds a high risk of damaging components due to increased handling. All this makes the process costly and reduces the capacity in core build.
It is a first objective of the present invention to provide a method for assembling a stator stage of a gas turbine engine with which the above-mentioned shortcomings can be mitigated, and especially providing a quick locking of a vane segment at a central section and facilitate a save assembling that also reduces costs.
It is a second objective of the invention to provide an adjustment pin to assemble the vane segment and the central section easy and quick as well as lock the central section properly. A third objective of the invention is to provide a use of an adjustment pin in the inventive method for proper locking of the vane segment in the central section of the stator stage.
These objectives may be solved by a method, an adjustment pin and a use of the adjustment pin according to the subject-matter of the independent claims.